Propulsion of ships



Spt. 6, 1932. G MARCQNNET 1,875,629

PROPULSION OF SHIPS Filed Dec. 2, 1930 Patented Sept. 6, 1932 i 1:11;;

UNITED STATES enonens MARCONNET, or rears, rnANoE;

rnorurisron or snrrs Application filed December 2, 1930, Serial No.499,585, and in France December 6, 1929.

The present invention relates to the propulsion of ships, and aims atreducing the resistance oflered to their progress by the friction of thehull in the water.

To this eflect, the invention consists of blowing a great number of airbubbles into the water along the sides of the hull, more particularly atthe frontof the ship. These air bubbles are meant to form a kind ofemul- 10 sion with the water which has a lower friction coefficient thanwater.

In order to put this procedure into practice, one can, for example,build the front part of the ship on a length of several yards and as faras it is under water, with a double hull. The space between the twowalls is supplied with compressed air under suitable pressure, and theouter wall is perforated by a great number of small holes which giveescape to air bubbles without interruptlon while the ship moves. 7

Since the latter advances, while the bubbles rise to the surface, thebubbles will slide along the oblique outlines of the hulls surface, andthus they will form a coat of emulsion starting at the bows, which willcover a great part of the surface of the hull.

If necessary, other perforated walls can be arranged on the sides of theshi for instance near the middle of its lengt so as to extend as much aspossible the advantage of the reduced friction in the water.

Calculations show that a slight reduction of the coefiicient of frictionis sufficient to obtain a marked reduction in the fuel consumption, thespeed remaining the same, or to in.- crease the speed of the ship withthe same consumption of fuel; this, taking into conby a second wall 2which forms together with the outer shell a narrow chamber which isconnected by a system of pipes to a blower. (not shown) which is fed byany kindof compressor. The outer wall is perforated by a great number oflittle holes 3 spread over I the whole immersed surface of the hull, andover a length, which can be, for example, equal to one tenth of thelength of the vessel, there being, for instance 250 holes per squaremeter. 1 These holes can have a diameter of 4 millimeters in the upperparts, and 6 millimeters in the lower parts. When the ship moves, airwill be com- 1 pressed in the chamber 1/2 at a pressure slightly inexcess of the water pressure at the level of the keel, so much so that agreat a 1 number of bubbles will escape from all the '65 perforations inthe ships side. Y These bubbles will rise along the hull and formagainst its walls an emulsion layer which will extend aft to a greateror lesser extent according to the speed of the ship, for 7 a instancecovering the trapezoidal surface a b c d. If one wishes to coveragreater .sur-- face of the sides of the ship, the chamber 1/2 can beextended backwards, especially in its lower parts, or one can arrangeperforations along the keel, for instance, in order to inject compressedair at all suitable spots.

If necessary, one can also subdivide the chamber 1/2 by longitudinalpartitions, and supply the superposed. compartments thus formed with airat a pressure corresponding to the depth of each below the water line.

In applying the present procedure to a ship already built, the actualhull would be used for theinner wall of the air chamber, .85 and onewould fix onto the outside of the hull a perforated wall kept at aslight distance from the former by suitable means.

The invention is, of course, not limited to this practical form, and themeans of inject ing compressed air into the water along the hull can bearranged in another form, perforatedtubes, flat nozzles, etc. a

One could also use in the place of air such gaseous fluids as may beavailable on board.

I claim:

In a ship, means for reducing the resistance offered to its advance bythe friction of the water comprising double walls disposed at: the frontpart of the ship so as to form a chamber for the reception of compressedgaseous fluid, means for introducing such fluid into said chamber, and aplurality of apertures formed in theouter Wall of said chamher forpermitting the escape of the compressed fluid, the cross-sectional areaof which apertures increases with their depth of ime mersion in theWater as and for the purpose described; i In testimony whereof I havesigned my name to this specification. p 7 r H GEORGES MARGONNET.

